User operated drug delivery devices are as such known in the art. They are typically applicable in circumstances, in which persons without formal medical training, i.e., patients, need to administer an accurate and predefined dose of a medicament, such as heparin or insulin. In particular, such devices have application, where a medicament is administered on a regular or irregular basis over a short-term or long-term period.
In order to accommodate these demands, such devices have to fulfil a number of requirements. First of all, the device must be robust in construction, yet easy to use in terms of handling and in understanding by the user of its operation and the delivery of the required dose or medicament. The dose setting must be easy and unambiguous. Where the device is to be disposable rather than reusable, the device should be inexpensive to manufacture and easy to dispose.
With patients suffering diabetes for instance, a blood glucose level has to be monitored and according to an actual measurement of said level an appropriate dose of insulin has to be administered on a regular basis. Blood glucose measurements as well as injection of a required dose of the medicament are quite often conducted by the patients themselves in different circumstances and situations. However, in rather dim or even dark environments, the process of piercing the skin may become rather difficult. Hence, a required degree of brightness or visibility for a lancing and/or for an injection process is not always available.
Document WO 01/41837 A1 discloses an injection device having a housing with a bow which can be pressed against and extend a skin surface where an injection is to be made. The bow is preferably made of a light transmitting material and can be illuminated by a lamp.
Moreover, document DE 33 22 923 A1 discloses an injection syringe with an illumination arrangement. There, the illumination arrangement is integrated into the syringe and is arranged lateral to the syringe for directing a focused light beam towards the distal tip of the injection needle. In this way, the site of needle puncture can be illuminated.
Even though various illumination arrangement already exist for syringe applications and injection devices, control and operation of the illumination requires a separate and additional interaction with the user or patient. In particular, the illumination has to be switched on and/or off separately. Also, the operation of an illumination arrangement is rather uncorrelated to the main functions of the injection device.
It is therefore an object of the present invention to provide a medical device having an improved illumination arrangement for illuminating a site of needle puncture in a comfortable and user-friendly way. The illumination arrangement should be easy and intuitively to control. The illumination arrangement should further improve user comfort and patient safety.